1. Field of the Invention
The present invention allows study and/or optimizing a production scheme for an oil reservoir. It evaluates the risks taken in terms of the development scheme, to compare several schemes, and to define an optimum scheme considering a given production criterion, for example oil recovery maximization, water recovery minimization or maintenance of the production rate at a given value for a given period. The present invention optimizes a production scheme in a probabilistic context. In fact, optimization is carried out by taking account of the uncertainties inherent in the reservoir.
2. Description of the Prior Art
Optimization of the production scheme is currently carried out according to two approaches:                by comparing each production scenario discretely, which is for example the case with the “nested simulation” [1] or “decision tree” [2] type approaches. This approach affords the advantage of combining several development options, but its cost in terms of numerical simulation is very high. Furthermore, it does not allow integration of uncontrollable uncertainties inherent in the reservoir (permeability, porosity);        by determining the optimum production configuration for a given reservoir while disregarding any form of uncertainty. Such studies using experimental designs have allowed providing an optimum production scheme, but by putting forward the strong hypothesis that there is no uncertainty on the geologic, static or dynamic of the reservoir [3].        
[1] [2] Ian Colins, “Decision Tree Analysis and Simple Economic Models Identify Technical Option Raking and Project Cost Estimates for Full Field Case”, WordOil, pp. 62–69, May 2003.
[3] Dejean, J. P. and Blanc, G., “Managing Uncertainties on Production Predictions Using Integrated Statistical Methods”, SPE 56696, SPE Annual Technical Conference and Exhibition, Houston, USA, Oct. 3–6, 1999.
Production scheme optimization is a very interesting problem because its goal is better management (in terms of cost, profit, safety, respect for environment) of the production of oil reservoirs. The method according to the invention allows studying production scheme optimization in a more general context than the context used so far : it allows optimization while integrating the various sources of uncertainty of the reservoir.